Improvement in the manufacture of saw-teeth



2 Sheets-Sheet 1'. I

N. W. SPAULDING. Manufacture of Saw-Teeth.

No. 205,311. Patehte'd June 25,1878.

. '2 Sheets-Sheet 2. N. W. SPAULDING.

Manufacture of Saw-Teeth. 7 No. 205,311; P aten tedlune 25,1878.

UNITED STAT s-PATE T OFFICE.

NATHANVW'I. SPAULDING, o'FsAN FRANCISCO, CALIFORNIA.

IMPROVEMENT IN THEfMANUFACTURE OF SAW-TEETH.

Specification for ing part of Letters Patent No. 205,311, dated June 25, 1878; application filed v p February 16, 1878. i

Toull whom it may concern:

Be it known that I, NATHAN W. SPAULD- ING, of the city and county of San Francisco, and State of California, have invented a new and useful Improvement in the Manufacture of Saw-Teeth; and I do herebydeclare the following to be a full, clear, and exact description thereof, reference being had to the accompanying drawings.

My invention has reference to the mahufac ture of insertible saw-teeth, and relates more particularly to a novel method and apparatus for giving form and body to the sheet-metal blanks from which such teeth are made.

I will first explain that these blanks arecut 'or stamped out of sheet metal in about the shape of an inserted saw-tooth. They are,

therefore in this stage of a uniform thickness at all points. A saw-tooth, however, requires to be'thicker through that portion extending from its cutting-point back 'to a line drawn upward coincident with the front edge of the body of the tooth, so that it will cut a kerf wider than the thicknessof the saw-blade, to give clearance and prevent friction of the blade against the sides of the cut.

' pressure is brought to bear upon the blank thatportion which extends into the mold will be spread, thickened, or upset, so as to fill and fit the mold.

My method of condensing or upsetting the pointof the blank which is. thus secured is by means of a sudden pressure exerted upon the back or upper edge of the blank, preferably produced by a drop-hammer, all as hereinafter more fully described.

Referring to the accompanying drawings,

Figure l is a perspective view of my machine.

- Fig. 2 is a view 'of 'a saw-toothbeforeand after spreadin g. Fig. 3 shows the under side of the drop-block. Fig. 4 is atop view of the machine. Fig. 5 is a horizontal section. Fig. 6 is a vertical section. Fig. 7 is a perspective of the two jaws or dies.

A is the pedestal or base upon which my ma chine is constructed. If I use a drop-hammer, (which I shall. ordinarily do,) I construct two upright guides, B B, on the pedestal or base, one on each side, and these guides I connect attheir upper ends by a cross-beam, O. D is the drop-block or driver, which is arranged to move between the guides B B in the usual way, and to which the forming-hammer is secured, as hereinafter specified; or a tilt-hammen or other device capable of exerting a blow or sudden pressure could be used, if preferred.

The tooth-holder I secure upon the pedestal or baseA, directly between the guides B B. It consists of a metal block or frame, El, which has an opening or chamber, preferably rectangular in form, passing down through it. In this opening or chamber I place the two dies or jaws F G. These jaws could both be made movable, or one can be made stationary and the other movable. I prefer the-latter plan.

In the present instance the die or jaw F is fixed in one side of the opening, and the other,

G, is movable to or from -it. A'pin passes through the side of theblock Hand-into a hole in the movable die,'so that the die can move to or from the fixed die upon it, but be prevented by it from moving up or: down.

The fixed jaw or die F has an open recess or"excavation, j, in its outer face correspond ing to the shape of the saw-tooth, while the movable jaw or die hasa corresponding projection, k, on its outer face. This projection is shallower than the recess, so that when the two jaws are forced together the projection will follow into the recess j. I therefore call this projection a follower.

7 Below that part of the follower k which corresponds with the point of a sawtooth I arrange one or more set-screws, o, and a projecting spiral spring, 0, as represented at Figs. 5 and 7. This follower and the'setscrews allow me to regulate the openingbr space between the two faces to fit and clamp blanks of different thicknesses. For instance, if the blank spring 17 forces it away from the fixed jaw.

is thin,'"Itu'rn the screwsfarther in, so as to allow the follower 'to"'enter the opposite corresponding recess a sufficient distance to firmly clamp the blank between the two opposing faces. If it is thicker, I turn the screws out, so asto lessen the amount of entrance of the follower. I am thus able to fit the dies to any desired thickness of blank.

The spring 19 extends outfarther than the set-screws, so that when the pressure on the movable die is relieved the spring will force" it back and release the tooth readily. I "alsocut away a thin portion of the outer face of each die extendin from near the middle of "blanJ t each die to the end where the point of the tooth is formed, thus leaving a space, on each side of the point of the blank extending about half the length of the back of the .tooth. The

remaining portion of the blank being clamped between the jaws, the throat of the blank will then rest upon the inclined ledge in the recess which corresponds with it.

' The movable die can be moved toward the fixed die by means of a cannwedge, or other mechanical power. I have represented a wedge,

'r, in the present instance, which passes through .a hole in the block H just behind the movable die, and projects from the block at one side.

-A lever-handle, s, is arranged to operate this wedge, so that by forcing the lever inward the movable jaw or die is forced toward the fixed jaw but by drawing it outward the pressure 'upon the movable jaw is relieved, and the I also make a series of holes horizontally through the wedge, near its outer end, and -when I-have ascertained the thickness of blank to be operated upon and the distance the'wedge must be forced in to clamp the movable jaw upon it, Iplace a pin in the hole ;nearest'that point, so that the workman need not exercise so great care in forcing the wedge j in, as the pin will stop it at the proper point.

I To facilitate the ready removal of the tooth from between the jaws or dies after it hasbeen formed, Iuse a lever, I, which is pivoted at its middle, one end of which extends under the ;-block and is turned upward, so as to form a .bearin g for the base of the blank or tooth to rest upon, while the opposite end projects outwardfrom the block H, so as to be operated conveniently by the workman.

' When the tooth has been formed and the jaws or dies separated, so as to release it, a

downward pressure on the projecting end of the lever will force the tooth upward, so that it can be grasped with a pair of tongs and removed from the recess. I

The hammer c, which is secured to the dropblock or driver D, is a narrow piece of steel, corresponding to the thickness of the tooth to be spread; and this hammer is arranged directly above the cavity in which the tooth-is placed, so that when the block is dropped the hammer will strike fairly upon the back of the blank or tooth. This hammer is removable,

so than-when desired,a thicker or thinner one can be substituted for it, according to the thickness of the tooth to be spread. The block or frame H is also adjustable side-wise, in order to permit the adjustment of the tooth'cavity to the hammer when a. thick or thin. tooth is being formed. This is accomplished by elongating the screw-holes in the lugs to, through which the screws pass which fasten the block to the bed-plate or base.

By loosening the screws the block can be shifted in either direction slightly, and again secured by turning down the screws.

Having ascertained the thickness of the o be spread, the first thing to be done is/ see that the-hammer is of a proper or corresponding thickness. Next I take out the movable die and set the set-screws to the proper point to regulate the width of the recess so that it will correspond with the thickness of the blank, and then replace it. I then adjust the recess to the hammer by shifting the block, and the machine is ready for use.

The blanks having beenproperly heated, I drop one, base downward, into the recess between the dies, so that the under side of its point will rest upon the inclined ledge in the recess. I then close the movable jaw upon it, so as to clamp it between the two jaws, as before described. The back part of the blank will be firmly griped and clamped between the jaws, while the point from near the middle of the back will rest in the enlarged portion of the recess upon the inclined ledge. The hammer is now allowed to drop upon the back of the blank. As it strikes the blank the rear portion, being, as before stated, clamped between two sides, which prevent it from spreading, and its upper edge being below the top of the sides, is forced downward between the sides, while the front portion or point, which rests upon the inclined ledge, is spread and thickened by the blow, so as to fill the enlarged recess, and thus give the. desired shape and formto the .tooth. The compression of the metal also draws the point forward, and any surplus metal is worked down the incline into the shank of the tooth and out at the tooth-point. This latter portion can be afterward trimmed off in pointing or sharpening the teeth.

Having thus described my invention, what I claim, and desire to secure by Letters Patble jaw has a corresponding. projection, is, on

its opposing face, said projection serving as a follower to admit of the adjustment of the die-faces to blanks of different thicknesses, iubstant-ially as and for the purpose herein set orth.

2; The fixed jaw or die F, provided with a In witness whereof I have hereunto set my recess or excavation, j, in its outer face, in hand and seal. combination with the movable jaw or die G,

with its projection is, and set screw or screws 0, NATHAN W. SPAULDING. [L. s.] the two jaws being secured in a block or frame,

H, and operated by a wedge, r, or equiva- Witnesses:

lent device, substantially as and for the pur- JNo. L. BOONE,

pose described. FRANK A. BROOKS. 

